Image processing machine capable of inhibiting copying of valuable papers

Abstract

An image processing machine having an electrophotographically making copies of one or more originals. This image processing machine is designed to inhibit the electrophotographic copying function in the event that one attempts to make a copy of valuable papers such as monetary papers or securities and comprises a detecting unit for detecting a spatial frequency of a small region of an original to be copied, a calculating unit for comparing the detected spatial frequency with a standard spatial frequency used as a standard pattern, thereby to calculate the degree of similarity therebetween, a judging unit for judging whether or not the degree of similarity so calculated is greater than a predetermined value, and a determining unit for determining, when the judging unit indicates the degree of similarity greater than the predetermined value, that the original to be copied is identical with an original used as a basis for the standard pattern.

What is claimed is: 
     
       1. An image processing machine which comprises: detecting means for detecting a spatial frequency of a small region of an original to be copied;   calculating means for comparing the detected spatial frequency with a standard spatial frequency used as a standard pattern, thereby to calculate the degree of similarity therebetween;   judging means for judging whether or not the degree of similarity so calculated is greater than a predetermined value; and   determining means for determining, when the judging means indicates the degree of similarity greater than the predetermined value, that the original to be copied is identical with an original used as a basis for the standard pattern.   
     
     
       2. The image processing machine as claimed in claim 1, wherein said standard pattern is a pattern of fringes contained in a monetary paper. 
     
     
       3. The image processing machine as claimed in claim 1, further comprising image forming means for forming an image on the basis of an image of the original, and wherein an operation of the image forming means is inhibited when the original is deemed identical with an original providing a basis for the standard pattern. 
     
     
       4. The image processing machine as claimed in claim 1, further comprising image forming means for forming an image on the basis of an image of the original, and wherein an operation of the image forming means makes a solid black print when the original is deemed identical with an original providing a basis for the standard pattern.